**Persistent northerly winds and widespread rain have kept Istanbul temperatures capped near 19°C on September 29, aligning with GFS and ECMWF model consensus.** Official forecasts from multiple sources project a daytime high of 19°C (67°F) under overcast conditions, with current midday readings around 18–19°C and light-to-moderate precipitation. This outcome sits slightly below the long-term September average high near 23°C, reflecting the stabilizing influence of the current synoptic setup rather than any anomalous warming. Trader sentiment heavily favors 19°C (89.5% implied probability) because observational data and short-range model runs show minimal upside risk, with only slight chances for 20°C if clearing occurs late in the day. No significant forecast revisions are anticipated before resolution.